Na-hyae (Hangul: 나혜 ; Alternate spellings: Na-hye), is a student that used to attend Yeondu High School before dying and becoming a mere ghost also known as "TThe Kid Solving a Problem" (문제 푸는 아이) in the remake.
- Main article: The Unsolvable Math Problem - School Ghost Stories (11)
- She has a texture that was found hidden in the game, however she is not seen in-game at any point. Only the sound of writing on the around the chalkboards of Classroom can be heard.
- She is only encountered in Main Building Section 1, but only in specific classrooms (Ex: 2-11).
※ She appears on Hard mode or above.
- Na-hyae makes a full appearance in which she is seen writing on the chalkboard, trying to solve the math problem.
- Ghost stories has changed in remake. Title has changed from "The Impossible Math Problem" (풀리지 않는 수학문제), to "The Math Problem Which is Solved Wrong" (잘 못 푼 수학문제) and it explains that she was top student, and she killed herself because of the shame.
- She appears to be writing on the chalkboard at Specific Classroom ( 2-7 ) and suddenly she might stop still, but with her hand still on the board. However, when approached she turns her heads to the player revealing that she had her eyes gouged and she yells something in Korean (내 눈이! / My eyes!) before disappearing.
- The document 'Class Announcement' gives a hint about where she appears.
- In the PC/PS4 version, Her 'Jump Scare' effect has been changed.
- Mobile ver : Bloody Workbook is on the table of the Reading Room at 4th floor, New Building.
And Chalk is on the desk of the Faculty Office 1 at 1st floor, Main Building Section 2
- PC/PS4 ver : Chalk is on the Blackboard of the Class room 2-8, at 2nd floor, Main Building Section 1.
And Bloody Workbook is on the floor at the Recording Room booth, at 2nd floor, Main Building Section 1.